Deep Insights: Diving Australia's kelp forests - Scott Bennett reflects on the Great Southern Reef

Scott Bennett and Graham Edgar from the GSR Research Partnership have been sailing around the Great Southern Reef surveying biodiversity as part of the Reef Life Survey lap of Australia. The team have sailed around the south west and across the Great Australian Bight, revisiting dozens of sites that were first surveyed back in the late 1990’s to understand how the reefs have changed.They are also surveying dozens of new sites, which have never been surveyed before. Blue groper are the largest carnivorous bony fish species found living on the GSR, reaching lengths well over a metre and weights of up to 40 kilograms. Counts of rings in the otoliths (ear bones) of blue groper have shown that this species can live for up to 70 years. It also takes around 15-20 years to reach sexual maturity, which alongside their inquisitive personalities and small home ranges make them especially vulnerable to overfishing. Despite its name the blue groper is not actually a groper (Family Serranidae) at all, but a member of the wrasse family (Labridae). All blue groper begin life as females and some, but not all, change sex to males later in life. The GSR supports both eastern and western blue groper. The separation of the two species can be traced back to the Ice Age, when waters became cooler and the blue groper population likely split and moved up the west and east coasts, so they could stay warm and in their preferred temperature range. By the time the Ice Age ended, it is thought that the western and eastern populations of blue groper had evolved in different ways over this period. When they then returned south to their previous distribution, they could not interbreed and remained in their separate western and eastern waters. Reflecting on his recent scientific expedition across the GSR, Scott Bennett emphasises that our reefs undergoing significant changes and the path to their preservation is twofold.As Scott poignantly notes, 'Early detection of unexpected changes is fundamental. It's how we begin to strategise and implement effective restoration and conservation strategies.'However, this is only part of the solution. Despite the GSR's invaluable contribution to Australian biodiversity, economy and culture, it suffers from a stark lack of research and monitoring funding. This gap in knowledge and preparedness leaves our reefs vulnerable to the accelerating impacts of climate change.In light of a recent Climate Council report, the stakes couldn't be higher. The ocean, our planet's buffer, has absorbed 93% of the excess heat from greenhouse gas emissions, with parts at risk of entering a near-permanent heatwave state by century's end without decisive action. This underscores the urgency of reducing fossil fuel emissions, aligning with Australia's goal to cut emissions by 75% below 2005 levels by 2030 and achieve net-zero by 2035.The call to action is twofold: aggressively cut emissions to mitigate the harshest impacts of climate change and significantly ramp up funding for research, monitoring, and restoration efforts for the GSR. Only by embracing this dual approach can we ensure the GSR's resilience and secure its benefits to all for generations to come. Let’s all work together to protect these precious habitats, understanding that our legacy will be defined by the actions we take today. Learn more at www.greatsouthernreef.com